A need exists for an improved wire bristle brush which (a) has an active bristle length which provides desirable flexibility for cleaning non-uniform structures such as cooking grates, (b) has a significantly longer life, and (c) significantly reduces or substantially prevents bristle breakage and loss during use.
For outdoor cooking grills, the cleaning of the cooking grate or grate assembly that supports the food during cooking is a matter of continual concern. After cooking, the user will want to remove any partially cooked food debris and/or char that remains on the surfaces of the food support structure so that the debris will not contaminate or alter the flavor, aroma, or other characteristics of the subsequently cooked food items.
Many methods and devices have been proposed over the years for cleaning outdoor cooking grates, including wipers, scrapers, and brushes. Wire bristle brushes are commonly preferred because the bundles of wire bristles which project from the brush have a length and flexibility which are more effective for reaching and abrasively cleaning the irregular surfaces, apertures, and/or other hard-to-clean features typically encountered in cooking grates. Fixed scrapers and other implements often cannot reach and/or cannot provide a sufficient amount of abrasive force for quickly cleaning such surfaces and features. Metallic wires are also preferred due to their suitability for contacting warm or hot cooking grate surfaces.
Brushes having wire bristles formed of stainless steel, brass, steel, aluminum, titanium and other metals are known in the art. The brushes used for cleaning cooking grates typically have wire bristles of from about 0.005 to about 0.010 inch in diameter which are formed of stainless steel or brass and are gathered together in bundles of from about 50 to about 100 bristles. Each bundle is typically attached to a base retaining structure formed of wood or plastic by gathering the wire bristles tightly together and punching the bundle into the outer surface of the base, in much the same manner that a stapler inserts each point of a staple into a blind hole.
To ensure that the wire bristle bundle is of sufficient length for both (a) insertion of a base end portion into the base retaining structure and (b) the subsequent intended use of the brush, the overall length of each bundle prior to insertion into the base will typically be at least twice the active bristle length required for the intended use. As used herein and in the claims, the term “active length” means the projecting part of a bristle or a bundle which will flex under load during use. The “active length” of the bristle or bundle extends from an initial bend point of the bristle or bundle to the distal end of the bristle or bundle. The initial bend point of each bristle or bundle under load is typically located at or substantially at the outer surface of the base structure. Typically, the active length of the bristle bundle projecting from the base will be in the range of from about 0.5 to about 1.0 inches.
A significant shortcoming of the current art is that, for brushes having a sufficient flexible active bristle length for cleaning cooking grates or other structures of similar complexity, the repeated flexing of the bristles under the force load required for such use will exceed the endurance limit of the bristles, thus resulting in the premature failure, breakage, and loss of a significant number of individual brush bristles over time.
Given the size of a typical brush, the size of a typical grill, and the number of times the grill is used per year, the cleaning brush can accumulate several tens of thousands of back and forth brush stroke cycles in the course of several years. Materials such as stainless steel and brass have endurance limits related to these back and forth movements under load which are only a fraction of the ultimate tensile strength of the material. As illustrated in FIG. 1, when used at load and stress levels which are below this endurance limit, the material will normally have a life of at least 10 million fully reversed (i.e., back and forth) stress cycles. However, as also illustrated in FIG. 1, if the stress level to which the brush bristles are exposed is higher than the endurance limit, then the brush bristles will have a shorter, finite life which declines exponentially (per the logarithmic Cycles scale used in FIG. 1) as the stress level is further increased.